DNS over TLS (DoT) is a protocol for the encrypted transmission of DNS (Domain Name System) queries. Name resolution on the Internet is typically transmitted unencrypted via UDP. With DoT, however, the assignment of domains and the associated IP addresses is encrypted using the Transport Layer Security (TLS) protocol. This protects the transmission from interception, manipulation and man-in-the-middle attacks.
DNS over TLS: Definition
DoT is the standard (RFC 7858) proposed by the Internet Engineering Task Force (IETF) for fortifying DNS connections. In contrast to conventional DNS requests, DoT establishes a secure TCP (Transmission Control Protocol) connection between the client and the DNS server, which is authenticated and encrypted using TLS.